Blender 2.79 on Mac Os 10.12 import csv data using Python
Use the os.path module 

I'm not on a mac.  The code you posted wont work on any os, unless you have a "/Users/dickmeehan/Desktopxyzevents.csv" csv file in your user folder.

import os

dirpath = "/Users/dickmeehan/Desktop"
filename = "xyzevents.csv"

filepath = os.path.join(dirpath, filename)
txt = open(filepath, "r")
quaketxt = txt.read()

txt.close()
print(quaketxt)


Note: If the blend file is saved then the folder it is in is 

blenfolder = os.path.dirname(bpy.data.filepath)


Use the filebrowser   

To avoid having to hardcode in paths altogether, open Text Editor &gt; Templates &gt; Operator File Import and edit any occurences of ".txt" to ".csv". (approx line 28)

# ImportHelper mixin class uses this
filename_ext = ".csv"

filter_glob = StringProperty(
        default="*.csv",
        options={'HIDDEN'},
        maxlen=255,  # Max internal buffer length, longer would be clamped.
        )


run the script, select the file... and bingo prints the selected csv file to system console.  Edit the read_some_data(..) method to suit.

Use the Text Editor

open the csv file in a text block (or paste into new  and rename)

for line in bpy.data.texts["xyzevents.csv"].lines:
    print(line.body)


Lastly

There is no need to convert to some unwieldy string.

csvtext = '''
number,y,x,z,m
1,0,0.44,8.19,11.21
2,-11.68,8.13,8.31,7.22
3,-1.54,1.42,5.93,2.16
4,-7.1,3.13,6.25,1.42
5,5.17,3.13,8,1.39
'''

print(csvtext)